Speaker
Dr
Yunbo Dong
(Southwestern Institute of Physics)
Description
In tokamak experiments, including JET, JT-60U, Tore Supra, and TEXTOR, it has been shown that the runaway electron (RE) generation occurs usually above a threshold at Bt ≈ 2 T independent on machine size. Recently, disruption mitigation experiments with SMBI and MGI have been carried out in the HL-2A and J-TEXT tokamaks to study various injection scenarios and gas jet penetration. The improved SMBI system has been developed at HL-2A with a larger orifice(0.5mm of diameter), a quite shorter opening time (0.2ms), and its maximum throughput is up to 1.0×10^21 (10ms，50bar). The SMBI was triggered by a negative voltage spike in the loop voltage signal prior to the thermal quench. In the SMBI mitigation experiments at HL-2A, the RE plateau is achieved even at Bt = 1.3 T, much lower than the Bt threshold observed in other tokamaks. Both Ne and Ar gases could create runaway electron at Bt = 1.3 T. In addition, A fast massive gas injection valve has been constructed and tested on the J-TEXT tokamak, whose shortest opening time is about 0.25ms and maximum gas capacity is 1.0×10^24. In J-TEXT disruption mitigation experiments, after injecting Ar to induce disruption, both Bt threshold and electron density threshold of the RE plateau generation are observed in J-TEXT. The threshold of Bt is 1.2T, similar to that found in HL-2A. The RE plateau is easier to obtain at lower electron densities. This might be understood by hot tail RE generation.
| Country or International Organisation | China |
|---|---|
| Paper Number | EX/P7-31 |
Primary author
Dr
Yunbo Dong
(Southwestern Institute of Physics)
Co-authors
Mr
Chengyuan Chen
(Southwestern institute of physics)
Prof.
Ge Zhuang
(Huazhong University of Science and Technology)
Dr
Huidong Zhuang
(Institute of Plasma Physics)
Dr
Jinming Gao
(Southwestern Institute of Physics)
Dr
Long Zeng
(Institute of Plasma Physics)
Prof.
Yi. Liu
(Southwestern Institute of Physics)
Mr
Yihui Luo
(Huazhong University of Science and Technology)
Dr
Yipo Zhang
(Southwestern Institute of Physics)
Prof.
Yuhong Xu
(Southwestern Institute of Physics)
Dr
Zhongyong Chen
(Huazhong University of Science and Technology)
